The present invention relates to automatic floor cleaning machines of the self-propulsion type having drive wheels, a pair of rotatably mounted floor-contacting members for washing, polishing and the like, and a dirty water vacuum pick-up in the form of a squeegee assembly located rearwardly of the floor contacting members; and, more particularly, to means for supporting, adjusting and lifting such assembly in relation to the housing or framework structure of the floor cleaning machine.
In the aforesaid floor cleaning machine it is important, for proper squeegee operation, that the floor-contacting squeegee blades of the squeegee assembly: maintain a generally perpendicular relationship to the floor; exert the proper pressure thereagainst regardless of the roughness or smoothness of the floor surface; and move quickly, easily and efficiently to an inoperative position spaced above the floor level when the squeegee action of the blades are not required, such as during blade replacement or polishing operations.
In copending U.S. application Ser. No. 186,420, filed Sept. 12, 1980 and assigned to the assignee of the present invention there is disclosed a squeegee assembly wherein the crescent-shaped vacuum housing of the squeegee-blade unit is disposed substantially along the arc of a circle the center of which coincides with the vertical axis passing through the midpoint of the extension of a diametral line between a pair of rotatably mounted circular floor treating units, such as brushes or buffers; and is universally supported at such center by means of a single rigid arm to thereby permit movement of the squeegee assembly about three perpendicular axes. As depicted in FIGS. 2 and 16 of the aforesaid application, this arm is pivotally affixed to the squeegee housing and cam means are provided to adjustably fix the pivot angle of the housing with respect to the support arm to thereby provide proper orientation of the squeegee blades with respect to the floor surface. In such prior application lifting of the squeegee assembly to its inoperative position above the floor is provided by means of an actuating handle and a separate multiple-linkage arrangement which acts upon the support arm causing the same to pivot upwardly about its universal mounting. An adjustable spring coacts with one of the multiple links to normally bias the squeegee blade unit into its operative, floor-engaging position.
In prior U.S. Pat. No. 3,065,490 of Nov. 27, 1962 to Arones, a straight squeegee vacuum housing is supported at each outer extremity thereof by a pair of parallel support arms; each of which being mounted for universal movement at opposite ends to permit lateral as well as vertical movement of the squeegee housing. Springs interconnect opposed ball-joints of each pair of arms to bias the squeegee housing in a downward, floor-contacting direction. To lift the squeegee housing to its inoperative position, means are provided in the form of a horizontally disposed cross-bar which is connected to a vertical strut at the rearward ends of each pair of arms. An actuating handle engages the cross-bar to thereby vertically lift the squeegee housing and its blades out of contact with the floor surface.